1. Field of the Invention
The present invention relates to a multilayer electronic component, an electronic device including the multilayer electronic component, and a method for producing the multilayer electronic component. In particular, the present invention relates to a multilayer electronic component having a multilayer structure including a resin layer disposed on a ceramic substrate, an electronic device including the multilayer electronic component mounted on a mounting board, and a method for producing the multilayer electronic component.
2. Description of the Related Art
For example, Japanese Unexamined Patent Application Publication No. 2004-14648 (Patent Document 1) discloses a structure in which a ceramic substrate is mounted on a mounting board. More specifically, the ceramic substrate includes a columnar conductor composed of a sintered metal, the ceramic substrate and the columnar conductor being formed by co-firing. The columnar conductor protrudes from the ceramic substrate. The columnar conductor is soldered to an electrode disposed on the mounting board side to mount the ceramic substrate on the mounting board.
On the other hand, for example, Japanese Unexamined Patent Application Publication No. 9-83141 (Patent Document 2) discloses a structure in which a semiconductor element is mounted on a multilayer ceramic substrate. More specifically, the multilayer ceramic substrate includes a columnar conductor composed of a sintered metal, the multilayer ceramic substrate and the columnar conductor being formed by co-firing. In the same way as in Patent Document 1, the columnar conductor protrudes from the multilayer ceramic substrate. The columnar conductor is soldered to an electrode disposed on the semiconductor element side to mount the semiconductor element on the multilayer ceramic substrate. The protrusion of the columnar conductor from the multilayer ceramic substrate results in the formation of a gap between the semiconductor element and the multilayer ceramic substrate. Patent Document 2 discloses that the gap is sealed with a resin.
Patent Document 1 also discloses that an electronic component is mounted on a surface of the ceramic substrate facing the mounting board. In this case, the electronic component may be sealed with a resin in order to ensure reliability by improving the environmental resistance of the electronic component.
However, as described in Patent Document 2, when the protrusion of the columnar conductor from the ceramic substrate is sealed with the resin so as to be completely buried in the resin, the resin layer is in contact with the mounting board or is in proximity to the mounting board. Thus, a relatively large stress is applied to the ceramic substrate and the electronic component mounted thereon because of deformation, such as deflection and strain, which possibly appears on the mounting board side. As a result, disadvantageously, the ceramic substrate has a structural defect such as a crack, the electronic component has a structural defect such as a crack, and the electronic component is detached from the ceramic substrate.